GSK adds bowel risk to Rotarix label

Some evidence has cropped up indicating that GlaxoSmithKline's infant vaccine Rotarix may boost the risk of a rare but potentially fatal bowel problem. It's intussusception--a condition in which the intestine twists or becomes obstructed--the same problem that doomed a similar vaccine from Wyeth in 1999.

Worried about a replay of the Wyeth vaccine withdrawal, FDA has been keeping an eye on Rotarix and its rival RotaTeq, made by Merck. GSK has been watching as well; it's conducting a postmarketing study of Rotarix's potential risks. This new red flag comes from a different study, however, conducted in Mexico. Preliminary results suggest that there is an increased risk of intussuseption in infants given Rotarix.

FDA says that applying the Mexican data to historical intussuseption rates in the U.S. "translate[s] to potentially 0-4 additional cases...per 100,000 infants within 31 days of receiving the first dose of Rotarix." The new data has been added to Rotarix's label, to keep doctors and patients apprised, and FDA plans to review the Mexican study's final results when they're available next year.

In a statement, GSK says it's "confident in the safety profile of Rotarix." Its history has been a bit mixed: The vaccine has been prequalified by WHO, a key stamp of approval, and a January study in the New England Journal of Medicine hailed it and RotaTeq as lifesavers, with the potential to prevent 2 million deaths over the next 10 years if widely used. But in March, the FDA and WHO suspended use of Rotarix when genetic sequencing found material from a pig virus in the vaccine. It was cleared for use again in May, after FDA confirmed that the viral material wasn't a danger.